1. Field of the Invention
The present invention relates, in general, to a tilting and telescopic structure for steering columns and, more particularly, to a tilting and telescopic structure with one tilt lever performing the tilting and telescopic function of adjusting the tilting angle and the length of a steering column in accordance with the body size of a driver.
2. Description of the Prior Art
As well known to those skilled in the art, it is preferable to provide steering columns with a means for allowing a driver to selectively adjust the position of a steering column in accordance with his body size, thus allowing the driver to stably and safely handle a steering wheel without having any inconvenience while driving a car. Typical steering columns are thus individually and preferably provided with both a tilting means for the column's angle adjustment and a telescopic means for the column's length adjustment.
FIGS. 1 to 3 show the construction of typical tilting and telescopic structure for steering columns. As shown in the drawings, a typical tilting and telescopic structure has two levers: a tilt lever 100 and a telescopic lever 200 and is operated as follows.
In order to adjust the tilting angle of the steering column, the tilt lever 100 is loosened, allowing the angle of a telescopic tube 400 to be adjustable. After the angle of the tube 400 is adjusted, the tilt lever 100 is fully rotated in a tightening direction, thus fixing the adjusted position of the tube 400.
In order to adjust the length of the steering column, the telescopic lever 200 is rotated in a loosening direction, thus moving two block bodies of a telescopic block 300 in opposite directions. The two block bodies are received in a column housing and are commonly fitted over an actuating screw 500 of the lever 100 in such a manner that they are always moved in opposite directions in accordance with a rotating action of the lever 100. The block bodies in the above state form a gap between the block 300 and the tube 400 and allow the tube 400 to be movable in either direction relative to a driver. It is thus possible to adjust the length of the steering column in accordance with the body size of the driver.
After the column's length is adjusted, the position of the column is fixed by rotating the lever 200 in an opposite direction or a tightening direction. In such a case, the two block bodies of the telescopic block 300 come into frictional contact with the outside surface 401 of the tube 400 at their rounded surfaces 301, thus fixing the tube 400. In the above structure, the actuating screw 500 is fixed to the lever 200 by a nut 600. The column housing is provided with a guide bracket 700 for preventing the block 300 from being unexpectedly separated from the housing.
However, the above tilting and telescopic structure is problematic in that it has two levers respectively performing tilting and telescopic functions, thus having a complex construction and increasing the manufacturing cost of the steering columns.